Ball valve having trunnion stop

ABSTRACT

A rotatable plug valve having trunnions rotatably mounting a plug member within the valve chamber thereof, which plug member is rotatable between open and closed positions and is precisely stopped at each extremity of rotational movement to positively control the flow of fluid through the valve. The valve is provided with a stop pin, which is disposed in a stop pin recess located generally parallel with the axis of the plug trunnions and is disposed in intersecting relation with one of the trunnion bores so that the stop pin is partially exposed along its length within the trunnion bore. Stop surface means on one of the trunnions is engageable with the stop member to limit rotation of the valve element at each extremity of its travel. The stop member is so related to the valve body structure as to prevent the stop pin from being sheared as high magnitude forces are applied thereto.

I. ,anw---" United States Patent [111 3,552,717

72 Inventor Alton D. Oliver 2,766,961 10/1956 Meusy 251/2s5x Houston,Tex. 3.l 86,682 6/1965 Pierson et al. 251/306 m] APPL 781328 PrimaryExaminer-Hem T. Klinksiek [221 Med 1968 Attorney.lames L. Jacksin [45]Patented Jan. 5, 1971 [73] Assignee ACF Industries, Incorporated NewYork ABSTRACT: A rotatable plug valve having trunnions a mrporamm Jerseyrotatably mounting a plug member within the valve chamber thereof, whichplug member is rotatable between open and closed ositions and isrecisely stopped at each extremity of I54] HAVING TRUNMON STOP rotatiolal movement t: positively control the flow of fluid ms, 5 Drawing Figs.

through the valve. The valve is provided with a stop pm, which [52] US.Cl. 251/285 is disposed in a stop pin recess located generally parallelwith lllt- 51/00 the axis of the plug trunnions and is disposed inintersecting [50] Field of Search 251/284- relation with one of thetrunnion bores so that the stop pin is 306 partially exposed along itslength within the trunnion bore. Stop surface means on one of thetrunnions is engageable with [56] References Cited the stop member tolimit rotation of the valve element at each UN STATES PATENTS extremityof its travel. The stop member is so related to the 1,484,643 2/1924Hansen 25l/286X valve body structure as to prevent the stop pin frombeing 1,814,534 7/1931 Van Etten 251/287 sheared as high magnitudeforces are applied thereto.

PATENTEUJAN 5mm 3552,71?

SHEET 1 OF 3 FIG. I

INVENIOR. ALTON D. OLIVER PATENTEDJAN 5197: I 3552,71?

SHEET 2 BF 3 INVIENI'OR .OLIVER HQ 3 BYALTON D I ATTORNEY PATENTEUJANSIB?! I 355271? sum 3 OF 3 INVEN'IUR. ALTON D. OLIVER ATTORNEY highforces thereto.

BALL vALvE HAVING ,rnunnlon sror BACKGROUND AND, DESCRIPTION or THEINVENTION-L" This invention is related generally-to. valves forcontrolling the flow of fluids, and more particularly to valves havingstop constructions for limiting movement of .a valve element to properlyalign a flow passage inthevalve element with flow passages defined inthevalve body.-.The -valve art is generally considered to bewell-developed, and valves having stop elements for limiting movement ofa valveelement between open and closed positions and for locating valveelements at the predetermined open position thereof-are quite wellknown.

Gate valves are generally provided with upper or lower stop memberswhich are engaged by the gatemember at the extremities of its travel toproperly align 'a'port within the gate with, flow passages through thevalve. Plug valves are frequently provided with stops which are-formedexteriorly of the valve body, which stops are engagedby devices carriedby the operating stem of the valve to determine the open and closedpositions thereof. Plug valves of the spherical plug type may utilizeexternal stops or may-be provided with a'slot or groove out within theplug whichdefines stop surfaces forengagementby a stop pin or projectioncarried by the valve body to limit plug rotation. I

It is frequently necessary to assure that the port through the valveplug achieves positive and precise alignment with the I flow passagesthrough the valve body to assure passage of line positions thereof andwhich stop devices are not susceptible to metal deformation which mightcause misalignment of the plug member relative to the valve passages.

Among the several objects of this invention is contemplated theprovision of a novel trunnioned ball'valve. having a stop constructionwhich is simple in nature, reliable in use, and low in cost.

Other and further objects, advantages, and features of this inventionwill become apparent to one. skilled inthe art upon consideration of thewritten specification, the attached claims,

' and the annexed drawings. The form of the invention, which possible toprevent misalignment offthe portsdue to metal deformation as therotatable ports of the valve are subjected to high torque forces. I 7

A primary disadvantage encountered in the manufacture of large valves,such as pipeline ball valves,- has been the tendency of stop memberssuch as pins to be sheared due to the extremely high magnitudeforces'which may be encountered at the extremities of plug rotation. Itis quite apparent, when viewing the state of the art, that virtually allstop members or stop surfaces are subjected to shearing forces and,therefore, are subject to being sheared upon the application ofextremely Plug alignment on initial assembly-is frequentlymade-difficult because of tolerances allowed during manufacture of partsfor the valve. A condition generally referred to as tolerance stack up"may be developed asthe parts are assembled where several allowabletolerances of the parts accumulate to such a degree that the plugelement may not positively align with the flow passages in the'openposition thereof. To manufacture the parts to closer tolerances wouldeliminate or render tolerance stack up" ineffective, but would. increasethe cost of manufacture to such an extent as'to detract from thecompetitive nature of the product.

It is, therefore, a primary object of this invention to provide anovelvalve structure, including a stop member which is capable oflimiting valve movement between the open and closed positions thereofand which is subjected only to compression forces upon being engaged bya stop surface.

It is a further object of this invention to provide a novel trunnionedplug valve, including a rotatable trunnion having a stop surface thereonwhich engages astop member to limit rotation of the valve elementin=such manner as to insure against shearing the stop member upontheapplication of high magnitude forces. I

It is an even further object of this-invention to provide a noveltrunnioned plug valve structure which is capable of being assembled insuch manner as to eliminate any misalignment which might be caused byaccumulation of manufacturing tolerances. I

It is another important object of this invention to provide a noveltrunnioned plug valve including internal stop devices for positivelylocating the plug member the open and closed Briefly, the inventionconcernswill now be described indetail, illustrates the generalprinciples of the invention, but it is "to be understood that thisdetailed description is not to be taken'as limiting since the scope ofthe invention is best defined byrthe appended claims. Such descriptionwill be'referred to by reference characters-in the drawing in which: I"i FIG. 1 is a sectional view of a trunnioned ball valve structureconstructed in accordance with the present invention.

FIG. 2 is a fragmentary sectional viewo f the lower trunnion trating thetrunnion stop and trunnionstop adjustment structure thereof in detail. I

FIG. Sis a sectional view taken along line 5-5 of FIG. 4, andillustrating adjustment and positivelocation of the trunnion stop andstop adjustment structure. i I

a trunnioned ball valve structure having a valve body defining avalvechamber. A spherical valve element or plug is rotatably mounted withinthe valve chamber upon upper and lower trunnion members,

closed positions. The stopcomprisesa pin member, whichis fully supportedthroughout its entire length by a stop support and adjustment member ofthe valve -'b o dy so that the pin member is effectively prevented frombeing sheared as the stop surface of the trunnion bears there against.The adjustment portion of the valve body provides a means for account-.

ing for tolerance accumulation during assembly of the valve componentsin such manner as toallow precise positioning of the stop pin relativeto the trunnion stop surface upon assembly of the valve. After theadjustment member has been properly installed, the rotatable plug memberwill be positively aligned with the flow passages of the valve in theopen position thereof.

Referring now to the drawings for a'more detailed description of theinvention,'a valve, which may be an end entry spherical plug valve asillustrated at 1 0 in FIG. 1, is provided with a valve body portion 12,thereof, defining a valve chamber 14. The body portion 12 of the valve10 is formed with a flow passage 15, which is disposed: in fluidcommunication with the valve chamber. The valve body may be providedwith a flange structure as illustrated at 16 in FIG. 1 or it may beprovided with a weld end construction for either bolted or assembly withthe valve body portion 12 by a series of bolts or threaded studs 22 anddefines a closure for the valve chamber.

The end closure member 20 is formed with a flow passage 23 which isdisposed in axial alignment with the flow passage 15.

The valve body 12 is formed with aligned upper and lower" bores 26 and28, respectively, whichrecfeive upper and lower trunnion members 30 and32, respectively, therein. Sleeve bearings 27 and 29, formed of anysuitable plastic or metallic bearing material, serve to reduce frictionbetween the valve body and the upper and lower trunnions. A sphericalplug member 34 having a flow passage 36 formed therein is -rotatablypositioned within the valve chamber 14 and is provided with oppositelydisposed generally cylindrical bores 38 and 40 which receive the innerextremities of the trunnions 30 and 32 respectively. The plug member 34is maintained in nonrotatable relation with the upper trunnion 30 by apair of pin members 42 which fit within mating bores formed in the plugand in the trunnion 30. A pair of pins 43 maintain a nonrotatablerelation between the lower trunnion 32 and the spherical plug 34. Anupper cap plate 44 is fixed to the valve body 12 by a series of capscrews 46 to serve as an axial thrust support for the upper trunnion 30.Thrust support for the lower trunnion 32 is provided by a combinationthrust support and stop adjustment plate 72, which will be described indetail herein below.

An enlarged bore 52, formed in concentric relation with the bore 26 inthe valve body 12, cooperates with the cylindrical surface of the uppertrunnion member 30 to define an annular packing chamber. A packingassembly 54, disposed within the packing chamber, establishes afluidtight seal between the trunnion 30 and the cylindrical wall 52 ofthe valve body 12. A packing adjustment fitting 56 is fixed to the valvebody and is disposed in fluid communication with the packing chamber. Anoperating handle structure 58 is fixed to the uppermost portion of theupper trunnion 30, in any desirable manner, and is manually rotated toinduce rotation to the trunnion 30 and the spherical plug member 34 foropening and closing the valve. The valve structure may also be providedwith any of various acceptable hydraulic electrically, or pneumaticallydriven operator devices for imparting rotation to the spherical plug ofthe valve within the spirit and scope of this invention.

The valve body 12 of the valve is formed with a pair of seat recesses 60in which are located a pair of seat assemblies 62 establishing sealingengagement between the valve body and the working surface 64 of thespherical plug member 34. As illustrated in FIG. 1, the seat assemblies62 include a seat ring 66 and a retainer ring 68 which cooperate toretain an annular elastomer sealing member 70 in interlocked assemblytherewith. The sealing member 70 is disposed for sealing engagement withthe working surface 64 of the plug member 34.

To provide for proper location of the plug passage 36 relative to theflow passages and 23, the valve is provided with structure to limitrotation of the trunnions thereof. With reference now to FIGS. 2 and 3,and forming an important aspect of this invention, a lower trunnionthrust support and stop adjustment plate 72 is fixed to the valve body12 by a series of bolts 74 extending through apertures 76 in the thrustsupport plate and being threadedly received in the valve body. A sealingmember 78, which may be of the resilient O-ring type, is disposed in agroove defined between the thrust support plate 72 and the valve body 12and serves to maintain a positive seal between the valve body and thrustsupport plate.

The plate 72 is provided with an internal blind bore 80 which receivesthe lowermost portion of the lower trunnion 32. A thrust washer 82formed of any suitable bearing material is interposed between the lowerportion of the trunnion 32 and the substantially planar bottom wall ofthe blind bore 80 and serves to reduce friction as the trunnion 32rotates relative to the support plate 72.

For the purpose of limiting rotation of a trunnion 32 relative to thesupport plate 72, the support plate is provided with a stop pin bore 84which extends upwardly from the bottom of the support plate 72 andintersects the blind bore 80. The axis of the bore 84 intersects thecylindrical wall of the blind bore 80 so that a major portion of thebore 84 is located outwardly of the cylindrical wall defining the blindbore 80. The uppermost portion of the bore 84 is defined by a stopsurface 86 which limits upward movement of a generally cylindrical stoppin member 88 loosely disposed within the bore 84. The stop pin 88 maybe composed of any one of numerous acceptable extremely hard materials.It is necessary only that the stop member 88 be sufficiently hard toprevent compressive deformation thereof as the stop surface of thetrunnion 32 is forced into engagement therewith. The stop pin 88 isretained within the bore 84 by a support plate 90, which is welded orotherwise fixed to the support plate 72 to permanently retain the stoppin in assembly with the thrust support plate. The trunnion member 32 isprovided at its lower extremity with-a generally planar stop surface 92which is so related to the'axis of the trunnion 32 and to the dimensionof the pin 88 that the trunnion 32 will rotate 90 from engagementwith.the surface at one extremity of rotation of the trunnion toengagement with the stop surface at the other extremity thereof. Forexample, as illustrated in FIG. 3 the trunnion 32 is located in the openposition of the valve as shown in full line and is rotatablesubstantially 90 to the closed position of the valve as illus trated indash lines. The planar surface 92 is also designed to allow slightBrinelling of the planar surface at each extremity thereof as the plug34 and trunnion 32 are rotated to the open and closed positions thereofunder maximum torque force conditions. Such Brinelling in addition toslightly deforming the surface 92 will provide additional bearingsurface support between the surface 92 and the pin 88 thereby providingfor substantial force distribution between the contacting stop surfaces.

As the stop surface 92 moves into engagement with the stop pin 88, asillustrated in FIG. 3, the pin member 88 instead of being placed inshear, as is ordinarily the case, will be forced against the supportingwall defined by the bore 84. The wall of the bore 84 therefore, providesadequate support for the pin 88 along the entire length thereof so thatthe stop pin is placed in compression only. I

With reference now to FIGS. 4 and 5, the valve is provided withstructure for precisely adjusting the stop pin 88 relative to thetrunnion 32 for the purpose of overcoming any misalignment which mighthave occurred during assembly due to accumulation of tolerances. Beforethe valve is assembled, the support plate 72 is provided with a pair ofdrill guide bores 94 as indicated above, the support plate 72 is fixedto the valve body by the series of bolts 74. The apertures 76 are largerthan the bolts 74 so that the support plate may be rotated severalthousandths of an inch within limits defined by the clearances betweenthe bolt apertures 76 and the bolts 74.

As illustrated in dash lines in FIG. 5, the stop surface 92 may nottouch the stop pin when the spherical plug is disposed in its properopen position. As shown in full line, the thrust support plate 72 hasbeen rotated counterclockwise to .bring the stop pin 88 into engagementwith the stop surface 92. This slight rotation will be sufficient toovercome any misalignment which might have occurred due to accumulationof tolerances and will allow the stop pin 88 to be brought into preciseengagement with the stop surface 92 while the plug member 34 ismaintained in the properly aligned position thereofA pair of alignmentapertures 96 are then drilled into the valve body 12 using the guidebores 94 so that the alignment apertures are precisely located relativeto the stop pin bore 84. The-guide bore and the alignment aperture arethen reamed to the same dimension and guide pins 98 are inserted intothe bores 94 and apertures 96 in close fitting relation therewith. It isonly necessary that the pins 98 be disposed in close fitting relationwithin the bores 94 and guide apertures 96 so that the thrust supportplate 72 is positively aligned and locked with respect to the stopsurface 92 on the lower trunnion 32.

It will be evident from the foregoing that I have provided a noveltrunnioned plug valve structure employing a simple and unique stoparrangement utilizing a stop pin which is placed in compression byengagement with a stop surface to limit rotation of a valve elementbetween open and closed positions rather than being placed in shear asis usually the case. Through utilization of this arrangement, the stopmember achieves the capability of withstanding extremely great forceswhich may be applied as the valve element is rotated either-to its openor closed position. Commercial advantage of the invention is enhanced bythe fact that the adjustment arrangement allows the manufacturing ofparts to quite wide tolerances since the trunnion stop may bepreciselypositioned relative to the trunnion during assembly. The valve stem stopstructure and the adjustment structure utilize a minimum number of partsthereby further promoting the competitive nature of the valvemanufactured. Therefore, it is apparent that this invention is one welladapted to attain all of the objects hereinabove set forth, togetherwith other advantages which will become obvious and inherent from thedescription of the apparatus itself.

It will be understood that certain combinations and subcombinations areof utility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theappended claims. As many possible embodiments may be made of theinvention without departing from the spirit or scope thereof, it is tobe understood that all matters herein set forth are as shown in theaccompanying drawings are to be interpreted as illustrative and not in alimiting sense.

lclaim:

l. A rotatable plug valve having a valve body defining a valve chamberand having inlet and outlet flow passages in fluid communication withsaid valve chamber, at least one trunnion member rotatably carried bysaid valve body, a plug member being disposed in nonrotatable relationwith said trunnion member and being rotatable within said valve chamberbetween open and closed positions thereof to control the flow of fluidthrough said flow passages, an elongated stop pin being supported bysaid valve body with the axis thereof in substantially parallel relationwith the axisof said trunnion member substantially planar, stop surfacemeans formed on said trunnion and being engageable in line contact withsaid stop means to limit rotation of said trunnion and said plug memberin either rotative direction thereof, said stop means being so relatedto said valve body that said stop means is subjected only to compressionforces upon being engaged by the stop surface means of said trunnion,whereby said stop member will not be sheared upon the application ofsevere forces thereto. 7

2. A rotatable plug valve as set forth in claim 1, said valve bodydefining at least one trunnion bore, a stop recess formed in said bodywith an axis thereof disposed in substantially parallel relation withthe axis of said trunnion bore, said stop recess intersecting saidtrunnion bore along a peripheral wall thereof, a stop pin disposedwithin said stop recess and having an elongated exposed portion thereofextending into said trunnion bore, said stop surface means of saidtrunnion engaging said exposed portion of said stop and compressing saidstop pin against the valve body wall defining said stop recess.

3. A rotatable plug valve as set forth in claim 1, said valve bodyhaving at least one trunnion bore, said trunnion member being rotatablyreceived within said trunnion bore, elongated stop recess means definedin said valve body and intersecting said trunnion bore along aperipheral wall thereof, an elongated stop pin receivedwithin said stoprecess in close fitting relation therewith and having an elongatedsemicylindrical exposed portion thereof extending into said trunnionbore, said stop surface means engaging the exposed portion of said stoppin and compressing said stop pin against the valve body wall definingsaid stop recess.

4. A rotatable plug valve as set forth in claim 1, said valve bodyhaving at least one trunnion bore, said trunnion member being rotatablyreceived within said trunnion bore, an elongated partially cylindricalstop recess formed in said valve body along an axis substantiallyparallel with the axis of said trunnion bore, a generally cylindricalstop pin being disposed within said stop recess and having a partiallycylindrical exposed portion thereof extending into said trunnion bore,said substantially planar stop surface engaging said exposed portion ofsaid stop pin along the length thereof and compressing said stop pinagainst the valve body wall defining said surface, whereby forcesexerted through said stop surface will be evenly distributed along theex osed length of said stop pin.

5. valve having a valve bo y defining avalve chamber and having inletand outlet passages in communication withthe valve chamber, a valveelement disposed within said valve chamber and being movable betweenopen and closed positions to control the flow of fluid through thevalve, a substantially planar stop surface means provided by said valve,an elongated stop member supported within the valve and being engageableby said stop surface means to limit movement of said valve element ineither direction thereof, said stop member being subjected only tocompressive forces applied in evenly distributed manner along the lengththereof through said stop surface means whereby shearing of said stopmember and excessive Brinelling will not occur upon the application ofsevere forces thereto.

6. A valve as set forth in claim 5, said valve body defining anelongated stop retainer recess, said stop member being disposed withinsaid recess and having a portion thereof extending into the path of saidstop surface means, said stop surface means engaging' said stop memberin line contact at each extremity of travel of said valve element andapplying force to said stop member in a direction toward said recess,whereby said stop member is supported by the wall defining said recessand is prevented from subjection to shear forces.

7. A valve as set forth in claim 5, said recess being partiallycylindrical, said stop member being a cylindrical pin disposed withinsaid recess, said stop surface means engaging said cylindrical pin alongthe length thereof and forcing said pin in a direction toward saidrecess.

8. A rotatable plug valve having a valve body defining a valve chamberand having inlet and outlet flow passages in fluid communication withsaid valve chamber, at least one trunnion member rotatably carried bysaid valve body, a plug member being disposed in nonrotatable relationwith said trunnion member and being rotatable within said valve chamberbetween open and closed positions thereof to control the flow of fluidthrough said flow passages, a thrust support plate being fixed to saidvalve body and having a stop recess formed therein, elongated stop meansdisposed within said stop recess, substantially planar stop surfacemeans formed on said trunnion and being engageable in line contact withsaid stop means to limit rotation of said trunnion and said plug memberin either rotative direction thereof, said thrust support plate beingadjustable to move said stop means into precise engagement with saidstop surface means upon assembly of said valve, thereby compensating forany accumulation of manufacturing tolerances.

9. A rotatable plug valve as set forth in claim 8, said thrust supportplate having drill guide bore means, alignment apertures formed in saidvalve body in precise alignment with said stop surface means, guide pinmeans being received in said drill guide bore means andsaid alignmentaperture means and locking said thrust support plate and said valve bodyin nonrotative relation.

10. A rotatable plug valve as set forth in claim 9, said thrust supportplate having a plurality of bolt openings therein, a plurality of boltsextending through said bolt openings and securing said thrust supportplate to said valve body, said bolt openings being substantially largerthan the diameters of said bolts whereby said thrust support plate maybe rotated a slight amount relative to said bolts during assembly tocompensate for said accumulation of tolerances.

1. A rotatable plug valve having a valve body defining a valve chamberand having inlet and outlet flow passages in fluid communication withsaid valve chamber, at least one trunnion member rotatably carried bysaid valve body, a plug member being disposed in nonrotatable relationwith said trunnion member and being rotatable within said valve chamberbetween open and closed positions thereof to control the flow of fluidthrough said flow passages, an elongated stop pin being supported bysaid valve body with the axis thereof in substantially parallel relationwith the axis of said trunnion member substantially planar, stop surfacemeans formed on said trunnion and being engageable in line contact withsaid stop means to limit rotation of said trunnion and said plug memberin either rotative direction thereof, said stop means being so relatedto said valve body that said stop means is subjected only to compressionforces upon being engaged by the stop surface means of said trunnion,whereby said stop member will not be sheared upon the application ofsevere forces thereto.
 2. A rotatable plug valve as set forth in claim1, said valve body defining at least one trunnion bore, a stop recessformed in said body with an axis thereof disposed in substantiallyparallel relation with the axis of said trunnion bore, said stop recessintersecting said trunnion bore along a peripheral wall thereof, a stoppin disposed within said stop recess and having an elongated exposedportion thereof extending into said trunnion bore, said stop surfacemeans of said trunnion engaging said exposed portion of said stop andcompressing said stop pin against the valve body wall defining said stoprecess.
 3. A rotatable plug valve as set forth in claim 1, said valvebody having at least one trunnion bore, said trunnion member beingrotatably received within said trunnion bore, elongated stop recessmeans defined in said valve body and intersecting said trunnion borealong a peripheral wall thereof, an elongated stop pin received withinsaid stop recess in close fitting relation therewith and having anelongated semicylindrical exposed portion thereof extending into saidtrunnion bore, said stop surface means engaging the exposed portion ofsaid stop pin and compressing said stop pin against the valve body walldefining said stop recess.
 4. A rotatable plug valve as set forth inclaim 1, said valve body having at least one trunnion bore, saidtrunnion member being rotatably received within said trunnion bore, anelongated partially cylindrical stop recess formed in said valve bodyalong an axis substantially parallel with the axis of said trunnionbore, a generally cylindrical stop pin being disposed within said stoprecess and having a partially cylindrical exposed portion thereofextending into said trunnion bore, said substantially planar stopsurface engaging said exposed portion of said stop pin along the lengththereof and compressing said stop pin against the valve body walldefining said surface, whereby forces exerted through said stop surfacewill be evenly distributed along the exposed length of said stop pin. 5.A valve having a valve body defining a valve chamber and having inletand outlet passages in communication with the valve chamber, a valveelement disposed within said valve chamber and being movable betweenopen and closed positions to control the flow of fluid through thevalve, a substantially planar stop surface means provided by said valve,an elongated stop member supported within the valve and being engageableby said stop surface means to limit movement of said valve element ineither direction thereof, said stop member being subjected only tocompressive forces applied in evenly distributed manner along the lengththereof through said stop surface means whereby shearing of said stopmember and excessive Brinelling will not occur upon the application ofsevere forces thereto.
 6. A valve as set forth in claim 5, said valvebody defining an elongated stop retainer recess, said stop member beingdisposed within said recess and having a portion thereof extending intothe path of said stop surface means, said stop surface means engagingsaid stop member in line contact at each extremity of travel of saidvalve element and applying force to said stop member in a directiontoward said recess, whereby said stop member is supported by the walldefining said recess and is prevented from subjection to shear forces.7. A valve as set forth in claim 5, said recess being partiallycylindrical, said stop member being a cylindrical pin disposed withinsaid recess, said stop surface means engaging said cylindrical pin alongthe length thereof and forcing said pin in a direction toward saidrecess.
 8. A rotatable plug valve having a valve body defining a valvechamber and having inlet and outlet flow passages in fluid communicationwith said valve chamber, at least one trunnion member rotatably carriedby said valve body, a plug member being disposed in nonrotatablerelation with said trunnion member and being rotatable within said valvechamber between open and closed positions thereof to control the flow offluid through said flow passages, a thrust support plate being fixed tosaid valve body and having a stop recess formed therein, elongated stopmeans disposed within said stop recess, substantially planar stopsurface means formed on said trunnion and being engageable in linecontact with said stop means to limit rotation of said trunnion and saidplug member in either rotative direction thereof, said thrust supportplate being adjustable to move said stop means into precise engagementwith said stop surface means upon assembly of said valve, therebycompensating for any accumulation of manufacturing tolerances.
 9. Arotatable plug valve as set forth in claim 8, said thrust support platehaving drill guide bore means, alignment apertures formed in said valvebody in precise alignment with said stop surface means, guide pin meansbeing received in said drill guide bore means and said alignmentaperture means and locking said thrust support plate and said valve bodyin nonrotative relation.
 10. A rotatable plug valve as set forth inclaim 9, said thrust support plate having a plurality of bolt openingstherein, a plurality of bolts extending through said bolt openings andsecuring said thrust support plate to said valve body, said boltopenings being substantially larger than the diameters of said boltswhereby said thrust support plate may be rotated a slight amountrelative to said bolts during assembly to compensate for saidaccumulation of tolerances.